19. sustain, abet, favor, assist; countenance, endorse. 29. retire, retreat, withdraw. 31. Back,hind,posterior,rear refer to something situated behind something else. Back means the opposite of front: back window.Hind, and the more formal word posterior, suggest the rearmost of two or more often similar objects: hind legs; posterior lobe.Rear is used of buildings, conveyances, etc., and in military language it is the opposite of fore: rear end of a truck; rear echelon.

Antonyms

1, 31. front.

Usage note

55. Although some object to their use, the phrases in back of and the shorter—and much older—back of with the meaning “behind” are fully established as standard in American English: The car was parked (in) back of the house. Both phrases occur in all types of speech and writing.

back

n.

Old English bæc "back," from Proto-Germanic *bakam (cf. Old Saxon and Middle Dutch bak, Old Frisian bek), with no known connections outside Germanic.

The cognates mostly have been ousted in this sense in other modern Germanic languages by words akin to Modern English ridge (cf. Danish ryg, German Rücken). Many Indo-European languages show signs of once having distinguished the horizontal back of an animal (or a mountain range) from the upright back of a human. In other cases, a modern word for "back" may come from a word related to "spine" (Italian schiena, Russian spina) or "shoulder, shoulder blade" (Spanish espalda, Polish plecy).

To turn (one's) back on (someone or something) "ignore" is from early 14c. Behind (someone's) back "clandestinely" is from late 14c.

To know (something) like the back of one's hand, implying familiarity, is first attested 1893. The first attested use of the phrase is from a dismissive speech made to a character in Robert Louis Stevenson's "Catriona":

If I durst speak to herself, you may be certain I would never dream of trusting it to you; because I know you like the back of my hand, and all your blustering talk is that much wind to me.

The story, a sequel to "Kidnapped," has a Scottish setting and context, and the back of my hand to you was noted in the late 19th century as a Scottish expression meaning "I will have nothing to do with you" [e.g. "Jamieson's Dictionary of the Scottish Language"]. In English generally, the back of (one's) hand has been used to imply contempt and rejection since at least 1300. Perhaps the connection of a menacing dismissal is what made Stevenson choose that particular anatomical reference.

v.

late 15c., "to move (something) back," from back (adv.). Meaning "to support" (as by a bet) is first attested 1540s. Related: Backed; backing.

adj.

Middle English, from back (n.) and back (adv.). Formerly with comparative backer (c.1400), also backermore. To be on the back burner in the figurative sense is from 1960, from the image of a cook keeping a pot there to simmer while he or she works on another concoction at the front of the stove.

adv.

late 14c., shortened from abak, from Old English on bæc "backwards, behind, aback" (see back (n.)). Back and forth attested from 1814.

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.Copyright (C) 2007 by HarperCollins Publishers.Cite This Source

backoff in Technology

networking A host which has experienced a collision on a network waits for a amount of time before attempting to retransmit. A random backoff minimises the probability that the same nodes will collide again, even if they are using the same backoff algorithm. Increasing the backoff period after each collision also helps to prevent repeated collisions, especially when the network is heavily loaded. An example algorithm is binary exponential backoff. (1996-05-28)